1. Field of the Invention
The present invention relates to a robot system for preventing accidental dropping of a conveyed object, comprising a robot which has a robot hand which can grip a conveyed object, and a control device which controls the motion of the robot.
2. Description of the Related Art
Usually, during a teaching operation for a conveyor robot, in order to prevent a workpiece from dropping during conveyance, it is necessary to ensure that the robot hand which grips the workpiece is released only when it has reached the destination table or tray etc. In relation to this, JP-A-H9-124267 proposes the art of preventing dropping of workpieces in a conveyor, which uses a clamp to suspend a workpiece for conveyance. More specifically, the conveyor of JP-A-H9-124267 comprises a confirming means which confirms if a workpiece is seated on a tray at the destination by using a sensor, and lifts the restrictions on motion of the clamp only when it confirms that the workpiece has been seated. However, when employing the art of JP-A-H9-124267, the robot hand has to be provided with dedicated sensors and mechanical parts which constitute the confirming means, and therefore the structure of the robot hand may become complicated and the manufacturing cost of the robot hand may increase. Further, in the art of JP-A-H9-124267, it is necessary to prepare sensors and mechanical parts which are suited for the dimensions and shapes of the individual workpieces, and therefore it is difficult to achieve a robot hand which can hold a wide variety of workpieces.
A robot system which can prevent accidental dropping of conveyed objects caused by a mistaken teaching operation for the robot hand even without dedicated sensors and mechanical parts etc. provided on the robot hand, has been sought.